Flexible polyurethane foams are widely used for applications requiring cushioning or damping properties. A distinction is drawn between ether-based and ester-based polyurethane foams due to the differences in the polyol base.
In general, polyether polyurethane foams are further processed to mattresses and seat cushions while polyester polyurethane foams are traditionally used in automobiles.
Most (i.e. .gtoreq.80%) of the flexible polyester polyurethane foams used in automobiles are in the form of laminated sheeting in conjunction with various surface materials. These laminated sheets are widely used in seats, backrests and headrests and also in roofs.
In addition to physicochemical properties, such as elasticity, high tensile strength and tear propagation resistance, solvent resistance and tackiness on melting, there are also compelling economic and processing reasons for the use of polyester polyurethane foams for the applications mentioned above.
However, substances which escape from the polyester polyurethane foams and can lead to visible deposits on glass surfaces are increasingly being regarded by consumers as a serious drawback.
This condensation of volatile constituents from the internal trim of motor vehicles on the inner surfaces of glass windows is known as "fogging". Fogging is a light-scattering film which impairs visibility. This is particularly a problem in poor lighting conditions.
The automotive industry has attempted to eliminate these drawbacks through the use of improved basic plastics and additives. However, the problem of fogging has still not been completely solved.
Now, the process according to the invention provides flexible polyester polyurethane foams which drastically reduce the fogging effect.